Red light implant for treating degenerative disc disease

Abstract

Red light-emitting implants for treating degenerative disc disease

Description

BACKGROUND OF THE INVENTION [0001] The natural intervertebral disc contains a jelly-like nucleus pulposus surrounded by a fibrous annulus fibrosus. Under an axial load, the nucleus pulposus compresses and radially transfers that load to the annulus fibrosus. The laminated nature of the annulus fibrosus provides it with a high tensile strength and so allows it to expand radially in response to this transferred load. [0002] In a healthy intervertebral disc, cells within the nucleus pulposus produce an extracellular matrix (ECM) containing a high percentage of proteoglycans. These proteoglycans contain sulfated functional groups that retain water, thereby providing the nucleus pulposus with its cushioning qualities. These nucleus pulposus cells may also secrete small amounts of cytokines as well as matrix metalloproteinases (“MMPs”). These cytokines and MMPs help regulate the metabolism of the nucleus pulposus cells. [0003] In some instances of disc degeneration disease (DDD), gradual ...

AI Technical Summary

Benefits of technology

[0008] Because one of the hallmarks of DDD is the degeneration of the ECM (leading to decreased disc flexibility), it is believed that red light irradiation of the disc will help the disc regain its flexibility.

[0010] In addition, low level laser therapy has also been found to prevent apoptosis in other non-cartilage systems as well. See Shefer, J. Cell Science, 115, 1461-9(2002) (skeletal muscle satellite cells) and Carnevalli, J. Clin. Laser. Med. Surg. 2003, Aug. 21(4), 193-6 (Cho K-1 cell line). Wong-Riley, J. Biol. Chem. 2004, e-pub Nov. 22, reports that irradiating neurons with 670 nm red light significantly reduced neuronal cell death induced by 300 mM KCN from 83.6% to 43.5%.

[0012] Without wishing to be tied to a theory, it is further believed that the red light irradiation of cells upregulates cytochrome c oxidase activity in those cells. Cytochrome c oxidase (also known as complex IV) is a major photoacceptor. According to Wong-Riley, Neuroreport, 12:3033-3037, 2001, in vivo, light close to and in the near-infrared range is primarily absorbed by only two compounds in the mammalian brain, cytochrome c oxidase and hemoglobin. Cytochrome c oxidase is an important energy-generating enzyme critical for the proper functioning of many cell lines. The level of energy metabolism in cells is closely coupled to their functional ability, and cytochrome c oxidase has proven to be a sensitive and reliable marker of cellular activity.

Problems solved by technology

In other instances of DDD, genetic factors, such as programmed cell death, or apoptosis can also cause the cells within the nucleus pulposus to emit toxic amounts of these cytokines and MMPs.

In some instances, the pumping action of the disc may malfunction (due to, for example, a decrease in the proteoglycan concentration within the nucleus pulposus), thereby retarding the flow of nutrients into the disc as well as the flow of waste products out of the disc.

This reduced capacity to eliminate waste may result in the accumulation of high levels of toxins.

In particular, the MMPs (under mediation by the cytokines) begin cleaving the water-retaining portions of the proteoglycans, thereby reducing their water-retaining capabilities.

This degradation leads to a less flexible nucleus pulposus, and so changes the load pattern within the disc, thereby possibly causing delamination of the annulus fibrosus.

These changes cause more mechanical instability, thereby causing the cells to emit even more cytokines, typically thereby upregulating MMPs.

As this destructive cascade continues and DDD further progresses, the disc begins to bulge (“a herniated disc”), and then ultimately ruptures, causing the nucleus pulposus to contact the spinal cord and produce pain.

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